Marine biopolymers

Chitin, a polymer of N-acetylglucosamine, is present in large amounts in the exoskeletons of crustaceans and other arthropods and is a major marine biopolymer 16). Its availability is, however, limited to byproducts from seafood industries (76). 

Recent innovations in filtration technology include tangential flow ultrafiltration methods that act as preconcentration methods for studies of marine biopolymers such as proteins (see also the section on Adsorption techniques below). 

Ben AC (2011) Chitin and chitosan Marine biopolymers with unique properties and versatile applications. Global J Biotech Biochem 6 149-153... 

With the nnmber of factors affecting the delivery of the bioactive compounds, namely, the nature of the polymers constituting the system, the nature of the drug, the structural and chemical featnres of the system, among others, the development of an appropriate drug delivery system needs to be addressed in a case-by-case scenario. Below, several examples of drng delivery systems based in marine biopolymers will be assessed. 

Chitosan is probably the most studied marine biopolymer for application in the development of drug delivery devices. More recently, the advent of chitosan-based nanomaterials has opened new possibilities in drug delivery, with particles exhibiting superior... 

Table 8.1 illustrates some examples of particles and capsules based on marine biopolymers aimed at the controlled dehvery of different types of drugs into several target tissues. 

Table 8.2 condenses information on illustrative examples of membranes and gels based in marine biopolymers aimed at the controlled delivery of drugs. 

Table 8.3 depicts information on examples of hydrogels and porous structures based in marine biopolymers aimed at application as scaffolds in cartilage tissue regeneration strategies. 

The same questions about the safety of organic flocculants have been raised ia other countries. The most drastic response has occurred ia Japan (7,77) and Swit2edand (77) where the use of any synthetic polymers for drinking water treatment is not permitted. Alum and PAC are the principal chemicals used ia Japan (7). Chitin, a biopolymer derived from marine animals, has been used ia Japan (80,81). Maximum allowed polymer doses have been set ia Prance and Germany (77). 

Another major component of the cell membranes are the lipopolysaccharides, which are present as phospholipid bilayers. Following the death of bacteria, the biopolymers that constitute their cell walls and membranes become part of the detrital organic carbon pool. The great abundance of these biopolymers in seawater and the sediments is a reflection of their resistance to chemical degradation and the important role that bacterioplankton play in marine biomass production. 

Kurita, K. (2006). Chitin and chitosan Functional biopolymers from marine crustaceans. Mar. Biotechnol. 8,203-226. 

Pomin, V. H. (2008). Review An overview about the structure-function relationship of marine sulfated homopolysaccharides with regular chemical structures. Biopolymers 91, 601-609. 

Our understanding of DOM composition and cycling has undergone a rapid change since the 1990s. Chemical studies of HMW DOM now show a composition that is rich in specific polysaccharides and proteins and remarkably uniform across diverse environments. These discoveries led Aluwihare et al. (1997) to propose that a major fraction of HMW DOM arises directly from biosynthesis. The concept that marine DOM has a large component of metabolically resistant bioploymers is a sharp departure from earlier ideas that described DOM as a mixture of simple biomolecules that had experienced abiotic transformation (geopolymerization) into HMW substances (fulvic and humic substances). Support for the directly formed biopolymer hypothesis comes from the chemical composition of HMW DOM itself. 

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